This invention relates generally to a racking or drawout mechanism for a circuit breaker, fuse truck, fused circuit breaker (hereinafter sometimes collectively referred to as "circuit device") and particularly to a two-way clutching system for a racking circuit device in and out. While the invention is described in connection with a circuit breaker, it is understood not to be so limited.
U.S. Pat. No. 4,693,132, issued Sept. 15, 1987, entitled Drive Mechanism For Drawout High Amperage Multi-Pole Circuit Breaker and U.S. Pat. No. 4,728,757, issued Mar. 1, 1988, entitled Interlock Scheme For Drawout High Amperage Multi-Pole Circuit Breaker, both in the names of Clifford A. Buxton, David C. Higgins and Gary A. Volesky and both assigned to Square D Company, respectively disclose a clutched arrangement for limiting the maximum torque applied when moving a circuit breaker between Disconnect and Connect positions to prevent damage to the breaker mechanism and an interlock for preventing access to or operation of the breaker under certain circumstances.
The present invention is a further improvement on the clutched drive mechanism of the '132 patent. It is also readily capable of providing a greater torque when removing the circuit device than when installing the circuit device. The benefit of this aspect of the invention is that while the torque during installation of the circuit device is restricted (as before), a larger torque is available during removal. Often a circuit device may be more difficult to draw out than it is to install due to a variety of causes including operational variations in the clutch mechanism. The invention assures that, whatever the reason for the difficulty, the circuit breaker or circuit device can be removed, which eliminates the need for working on a live circuit or for shutting down the circuit feeding the circuit device.